The aim of this study was to determine the effects of breeder age and stocking density on performance, carcass characteristics and some stress parameters (H-L ratio, serum glucose, cholesterol and triglyceride levels, tonic immobility test (TI), antibody production, relative asymmetry (RA) and external appearances). This experiment was carried out with 705 one-day old male broiler chicks (Ross ...

Fertility reduction due to sub-fertile males is a major concern in breeder flocks. Phenotypic traits of broiler breeder males and their relationships with fertility can be used as reliable indicators for identification and removal of sub-fertile males from the breeder flocks. This study was conducted to investigate semen traits (semen volume, sperm motility, sperm viability and sperm count) and...

Intraguild predation of Neoseiulus cucumeris Oudemans (Phytoseiidae) by soil-dwelling predators, Dalotia coriaria Kraatz (Staphylinidae) may limit the utility of open rearing systems in greenhouse thrips management programs. We determined the rate of D. coriaria invasion of N. cucumeris breeder material presented in piles or sachets, bran piles (without mites), and sawdust piles. We also observ...

Ceramic foam or cellular ceramics are proposed as a new solid breeder material configuration. Such cellular breeder materials would have an open cell structure consisting of a network of three-dimensional interconnected ligaments. Ceramic breeder foams could address some of the challenges facing packed breeder beds and potentially enhance thermal performance, increase breeding ratio, and improv...

Sexual selection has a critical role in evolution, and it is fundamental to identify what ecological factors drive its variation. Disentangling the ecological correlates of sexual selection over the long term, however, is challenging and has rarely been done in nature. We sought to assess how demographic changes influenced the intensity, direction and form of sexual selection and whether select...

In highly social species, dominant individuals often monopolize reproduction, resulting in reproductive investment that is status dependent. Yet, for subordinates, who typically invest less in reproduction, social status can change and opportunities to ascend to dominant social positions are presented suddenly, requiring abrupt changes in behaviour and physiology. In this study, we examined mal...

Group size has been shown to positively influence survival of group members in many cooperatively breeding vertebrates, including the Lake Tanganyika cichlid Neolamprologus pulcher, suggesting Allee effects. However, long-term data are scarce to test how these survival differences translate into changes in group extinction risk, group size and composition. We show in a field study of 117 groups...

Recent trends occurring in broiler primary breeding companies are described. The structure and operation of broiler primary breeder companies are described from pedigree elite populations, through great-grandparent and grandparent generations, down to the parent stock. The relatively low value of fertility and hatchability, compared with yield and feed efficiency as selection traits, is assesse...

• The spontaneous development of generalized arteriosclerosis in several strains of repeatedly bred male and female rats has been reported. The arterial lesions remain microscopic in the male but in the female breeder the lesions become more prominent and can be easily recognized grossly. Of particular importance is the fact that these arterial lesions develop spontaneously although the rats ar...